﻿Flames of Gases containing Carbon. 211 



two prisms, which were inserted at the minimum of deviation 

 for D, and a telescope magnifying six times. The following are 

 the results of the readings, with the addition also in the proper 

 places of those of the lines of potassium, sodium, and lithium : — 



304 K «. 



285 Extreme red. 



278 Li a. 



260^ 



257 | 



254 y Group of five red lines. 



252 | 



250J 



246 Sodium-line. 



233^ 



230 | 



227 y Group of five yellowish-green lines. 



225 



& 



222, 



201 1 Group of three pea-green lines, to which also fol- 



198 I lows a fourth, when the intensity of light of the 



195 J flame is especially great. 



160^ 



157 I 



155 ( 



153 I 



Group of four bright-blue lines. 



112 

 107 



Boundaries of a broad blue band, brightest in the 

 middle, and becoming gradually fainter towards 

 the edges. 

 103 Narrow bright-violet line. 

 J 101-5 1 Boundaries of a bright dark-violet band, brightest 

 1 98 J in the middle (100). 

 82 Violet end. 



It is thus seen that the group of five red lines is situated 

 between the lithium and the sodium line ; the three first lines 

 are at equal distances from each other, and are sensibly of 

 equal breadth ; the distance of the third line from the fourth, 

 and of the fourth line from the fifth is somewhat less, as is also 

 their breadth, though in a degree less evident to the sight. As 

 regards intensity of light, this group is circumstanced like the 

 others ; that is to say, the first or least-refracted line is the 

 brightest, whilst each succeeding line is fainter, the last being 

 faintest of all; this diminution of brightness, however, is not 

 so striking as it is, for example, in the lines of the group y, and 

 may perhaps even be regarded as merely the effect of con- 

 trast. 



P2 



